Efficiency Stabilization in Blue Organic Light-Emitting Devices Fabricated Utilizing a Double Emitting Layer with Fluorescence and Phosphorescence Doped Layers

Abstract

The luminance efficiency of the blue organic light-emitting devices (OLEDs) fabricated utilizing a double emitting layer (DEML) with a 4,4'-Bis(2,2-diphenyl-ethen-1-yl)diphenyl (DPVBi) layer doped with 4,4'-Bis[4-(diphenylamino)styryl]biphenyl (BDAVBi) fluorescence dopant and a 4,4'-Bis(carbazol-9-yl)biphenyl (CBP) layer doped with a bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium III (FIrpic) phosphorescence dopant at 20mA/cm(2) was 6.2 cd/A, indicative of highly efficient OLEDs. Electroluminescence spectra for the OLEDs with a DEML showed that a dominant peak at 469nm corresponding to the BDAVBi doped DPVBi layer together with a shoulder at 491nm related to the combination of the BDAVBi doped DPVBi layer and the FIrpic doped CBP layer appeared.